Automatic system of intercommunication.



- f PATENTE D OCT. 16, 1906. A. VAN WAGENEN.

AUTOMATIC SYSTEM OF INTERGOMMUNIGATION.

APPL'IOATION FILED JULY 31 1902. RENEWED MAE. 3, 1906.

B SHEETS-SHEET 1.

WITNESSES: 1 INVENTOR 7ZM W BY ATTORNEY-s N0. 838,429. PATENTED 001116, 1906.

' A. VAN WAGENBN.

AUTOMATIC SYSTEM OF INTERCOMMUNIGATION.

APPLIOATION FILED JULY 31, 19 2. RENEWED MAR. s, 1906.

a SHEETS-SHEET 2.

ATTO R N EYS No. 833,429. V PATENTED OCT. 16, 1906.

A. VAN W-AGENEN. AUTOMATIC SYSTEM OF INTERCOMMUNIUATION.

APPLIOATION FILED JULY 3 1, 1902. RENEWED MAE. 3, 1906.

8 SHEETS-SHEET 3.

' ATTORNEYS No. 888,429. PATENTED 0011.16, 1906. A. VAN WAGENEN.

AUTOMATIC SYSTEM OF INTERGOMMUNIGATION.

APPLIOATION FILED JULY 31, 1902. RENEWED MAR.8,1906.

8 SHBETS-SHEET 4,

WITNESSES: INVENTOR ATTORNEY5 PATENTED OCT. 16, 1906.

A. VAN WAGENEN. AUTOMATIC SYSTEM OF INTERGOMMUNIGATION.

APPLICATION FILED JULY 31, 1902. RENEWED MAR. 3, 1906.

8 SHEETSSHEET 5.

INVENTOR 1% W TTORNEYS No. 833,429. PATENTED 0013,16, 1906.

A. VAN WAGENEN. AUTOMATIC SYSTEM OF INTERGOMMUNIUATION.

APPLICATION FILED JULY 31, 1902. RENEWED MAE. 3, 1906.

8 SHEETSSHEET 6.

No. 833,429. PATENTED OCT. 16, 1906. A. VAN WAGENEN. AUTOMATIC SYSTEM OF INTEROOMMUNICATION.

APPLIOATION FILED JULY 31, 1902. RENEWED MAE. 3, 1906.-

8 SHEETS-SHEET 7.

INVENTOR- wMtsszs: 'Y I TT'ORNEYS I PATENTED OCT. 16

A. VAN WAGENEN. AUTOMATIC SYSTEM OF INTERUOMMUNICATION.

APPLIOATION FILED JULY 31, 1902. RENEWED MAR. 3, 1906.

8 SHEETSSHBET 8- ATTOR N EYS.

rmirnn srafrss M r llFifilliUllil.

AUTdIVlATIC SYSTEM 9F INTERCOIVIMUNICATION.

No sea r29.

Specification of Letters Patent.

Patented Oct. 16, 1906.

Application filed July 3 1, 1992. Renewed March 3, 1906. Serial No. 304.050.

To all 1071,0711 (It may concern.-

Be it known that I, ANTHONY VAN VVAGE- NEN, a citizen of the United States, residing at Sioux City, in the county of lNoodbury and State of Iowa, have invented certain new and useful Improvements in Automatic Systems of Intcrcommunication; and I do hereby declare the following to be a full, clear, and. exact description of the invention, such. as will enable others skilled in the art to which. it appertains tomake and use the same.

My invention relates to improvements in automatic systems of intercommunication, such involve the use of a plurality of separate instruments of communication with electric circuits therefor leading to a central station and automatic central-station switches by which different instruments of communi cation may be placed in operative connection at will.

My invention consists in novel means of supplying current both for the several instruments of communication of the system and for the switching instruments and circuits from a single battery or other source of electric current and in many other features, as hereinafter pointed out in the claims.

My invention is particularly intended for use in automatic telephone systems and in the following description will be deseriliicd in its application to an automatic telephone system; but it will be obvious that the invention is likewise adaptable for other systems of intercommunication such, for example, as telegraph systems, fire-alarm systems, hotel signaling systems, and the like. In these various systems of intercommunication the instruments which are intended to be directly operated by the persons who desire to communicate with each other (such,

for example, in automatic telephone sys tems, the telephone instruments themselves and the calling instruments by which the central-station switches are operated) are commonly caller subscribers instruments and will be so called herein, although it will be understood that by so doing I do not limit the use of the herem-descr1bed system in any way.

M7,. 2. -W, The 0 o l cts oi my in v ention are to supply u rub-er acts,

with mi:

of wires a a miuin'iuninumb to secure perfect secrecy, and to make the system as simple, economical, and free from liability to derangement as possible.

I will now proceed to describe my system with reference to the accompanying drawings, in which the application of my invention to an automatic telephone system such as that covered by the patent to Clark, Ellacott, and Johnson, No. 582,578, dated May 1.1, 1897, is illustrated and will then point out the novel features'in claims.

In the said drawings, Figure 1 shows diagrammatically the application of my invention in a simple form to a system consisting of two subscriber s stations only. Fig. 2 shows diagrammatically the application of my invention to a system comprising three subscribers stations, the wiring at the subscribers stations and at the central station being illustrated in greater detail. Fig. 3 illustrates an alternative arrangement of circuits similar to that of Fig. 2, but in which central-station switches having a double row of contact-points were employed. Fig. 4 is a similar diagrammatic view illustrating a fur-, ther alternative arrangement of circuits.

Fig. 5 is a view similar to Fig. 1, illustrating an alternative arrangement in which the switch magnets supply the inductive rcsistance necessary for the operation of the sys tem. Fig. 6 is a view illustrating the application of the arrangement of Fig. 5 to a system of three stations, a grounded circuit being shown. may be operated from the central-station battery. Fig. 8 shows the use of two central-station batteries, one of which supplies the current for operating the central-station switches, the other for the operation of the 5 telephone instruments.

Referring first to Fig. 1, the subscribers stations of that figure are designated by reference-letters A and B and the central station by C. receiver-hook switch-es 1 1 and telephone-receivers 2 2, thetelephone-transmitters and the wiring for the receivers and transmitters being omitted. 3 3 are the calling-transmitters, by the operation of which the cen- I0 5 trill-station switches are operated. i I do not limit myself to the use of any particular calling-transmitter, but may use that shown in Patent No. 588,511, granted to me Au ust 17,?

1897. Such calling-transmitters usual y com- 1 I o prise adial and suitable contact mechanism, so that when the (i131 or :LPOKJiAlDGZ ar- Fig. 7 shows how the call-bells go The drawing shows the ordinary 10o lines 8 and 9, leading from the central station conductors and 11 likewise connect stamagnets 4 and 5. nets necessarily I p I duction, and hence act as retardation-coils. 4

- glljconnected to av bus-bar 15 throu h non-inf-ductive resistances 16 in permanent connection with each other. One side of each calling-transmitter 3. is COD:-

v other side of nected to the opposite through Wire 18, common 'wire of the calling-transmitters ofa number Clark, Ellacott, and Johnson above men- 'contacts which are closed by the operation a common source of electric energy for supplying cur- I rent to the s stem and located, preferably, at the centre station is connected on one tardation-coils?) 13 and 14, and is also coning such that the telephone-wire connected ranged in connection therewith is set to any particular number or space thecircuit controlled by said -calling-transmitter is completed and broken a number of times .corresponding to the particular position to which t e dial or its pointer has een set, thereby operating the central-stationswitch a corresponding number of times. At the central station the. numerals 4 and 5 desi nate the operating-magnets of the centra -station switches correspondingto stations A and B, res actively. he construction of the centra -station switches is not indicated; but I may use the switch shown in the patent to tionedor the switch shown in myPatent No. 702,684, dated June 17, 1902. The switchat 6 and 7'. These contacts are to connect telephone or service maticall arrange to stations A and B, respectively. Other tions A and B with the central station, and battery 12 or other suitable side-to telephone-wires 8 and 9,throu h inductive' resistances (commonly terme renected to aret frh wire' 18, usually a common return, the other side of the battery being connected/to wires 10 and 11 (commonly termed switch-wires) through switch- The coils of these maghave considerable self-in Wires 10 and 11 are likewise permanently and 17, an henceare nected to tife 'central-station'battery throu h the corresponding switch-wire 10 or 11. T e

eac calling-transmitter is conpole of battery 12 y termed the com' mom-return v wire', since, as hereinafter shown, this wirenfayserve as the returnof stations. It does not form a part of the telephonic circuit in the particular arrangement of circuits shown inFig. 1, beingused only during the operation of the central-station switches and of the call-bells."

The telephone -'wires, switch-wires, and] common-return wires are all connected to the receiver hook switches at the subscribers stations, the mechanism of the switches betrical connection,

to any particular switc is in circuit with the 1 I common-return wire or with the correspondv| ing switch-wire," according as the receiverhook 1s depressed or,elevated. Normally a circuit is complete (except inso far as it ma be interrupted by contacts-'iwithin the cal ing-transmitter) from one pole of battery 12 through the switch-wire and common-return wire of each sub'scribers station to the opposite pole of the battery. Each subscribers calling-transmitter 3 is therefore in condition for operation at all times, and when one of them is operated it closes the contact (6 or, 7, as the case may be) of the corresponding central-station switch, thereby placing the telephone-wires 8 and 9 in communication. Subscribers stations A and B are then connected by a circuit consisting of wires 8 and 9 and common-return wires 18., There is no battery in this circuit; but said circuit serves nevertheless for the operation of call-bells or other signaling devices not shown in Fig. 1,

but shown in subsequent figures. As soon as the telephone-receivers are lifted from their hooks the stations A and B are connected by a circuit comprising telephone-conductors 8 and 9,. switch-conductors 10 and. 11, non-inductive resistances 16 and 17 and busbar 15. There is no battery in this circuit either; but since battery 12 is bridged across. I

this circuit at the central station there is a battery-circuit for each-subscribers station,

the current of which battery serves for the operation of the subscribers telephone instruments, and while the battery-current does not pass from stationyA to station B, but only from the central station to both station A and station B, nevertheless telephonic current fluctuations produced in'conductors 8-and 10, for example, by the operation of the telephone instruments at station A will pass'through the Switgh-contact at the central" station and through the non-inductive resistances 16 and 17 and bus-bar 15to wires 9 and 11 of station B, and so to the telephone instruments of that station. These telephonic'fluctuations, as is well known, pass through the longer circuit comprising corrductors 8 and 10 and9 and 11,which circuit,

' for placing the subscribers stations in' elecand a central-station bat ed across theteletery,which, although brid phone-circuit and there ore incapable of subscribers station to another, nevertheless supplies current both for the operation of the although perhaps of relatively high ohmie re- 'sistance, has low inductive resistance, since jiveresistance by reason of the inclusionin 1'2 c ausing battery-current to pass from one the contact-arm 20 0f the corresponding telephone instruments of each station and of the central-station switching instrument for each station.

Fig. 2 shows in greater detail how a plurality of subscribers stations may-be connected with a central station and. through the instrumentality of central station switches-may be connected to each other according to my system. The said figure shows three subscribers stations, (lettered D E F, respectively) and a central station G, having automatic central-station switches correspcndin each to one of thesubscribers stations and ettered D, E, and F, respectively. The several receiver-hook switches of this figure are all numbered 1, the telephone-receiver's'are all numbered 2, the calling-transmitters are all numbered 3, the telephone-wires are all numbered 8, the switchwires are all numbered' 10, and the retardation-coils are all numbered 13. 12 designates the battery for sup lying current to the system, ,15 the centre -stat1on bus-bar, 16 the non-inductive resistances in circuit with this bus-bar, and 18 designates the common return-conductor connected to bus-bar 19, formin one terminal of battery 12, to which busar the retardation-coils 13 are likewise connected. In this figure the automatic central-station switches are represented conventionally by the conventional repr'esentation of a magnet 4, having adjacent thereto a contact-arm 20 in proximity series of contact-points arranged in circular series. The spaces in this series'corresponding to the normal position of the contact arm and to the particular subscriber's station to-which each particular switch belongs are customarily left blank. The telephone-wire 8 of each subscriber s station is connected to switch and is further connected to one of the contact-points of each of the other centralstation switches of the system. The contactarm 20 of switch D" isshown in the position contact-arms of the other central-station switches being shown in. their normal positions. With the switch-arm of D the position shown a telephonic circuit connectj ing stations D and F may be traced as follows: from the receive r-hook switch 1 of station l through telephone-wire 8 of that station in con tact-arm 20 of central-station switch 1), thence through the telephone- {wire 8 of station F to the receiver-hook witch 1 ol that station, and thence'through je telephone receiver andtransmitter (supposing, ef course, that the receiver-hook 18 up) through the switch-wire 10 of station F to bus-bar 15, and thence through. the switchwire 10 of station D and. the telephone transanitter, and receiver of that station and through the receivenhool; switch 1 of station D (supposing, of course, thatv that retoathat of station D--wishes to place himself in communication with any of the other subscribers-as, for example, that at station F he operates his calling-transmitter 3 (the re ceiver-hook switches being down, as shown in the drawings) by setting his dial for station F, and this causes the calling-transmitter to send through the switch-circuit of station D (comprising switch-wire 10 ofthat station, the 'magnet 4 of central-station switch D, battery 12, and return conductor 18) a number of current impulses suflicient to move the switch-arm 20 into contact with the terminal of that switch to which the tele-. ghone -wire 8 of station F is connected, (this sing the osition' of contact-arm 20 of switch D s own in the drawings.) Upon the conclusion of a conversation the'sub scriher at station=D' returns the dial of his calling-transmitter 3 to normal, and thereby the contact-arm'ZO' of the corresponding central-station switch is likewise returned to normal. In Fig. 2 I have shown an ordinary magnetmgenerator" 22 and corresponding call-bell 23 ateach subscribers station in a local circuit extendingirom the lower contact point ofthe receiver-hdok switch 'tothe common-return line 18. The alternatingcurrent impulses produced by these magneto.- generators pass through the telephonic circuit when the latteris established,- for the reason that the full telephoniecircuit has.

less inductive resistance than the circuit formed by the central-station bridge, in

which bridge" inductive res'istance'is interto connect subscribers stations D and F, the p ose In 2 telephone-transmitters 24 are shown a the subscribers stations as well as telephone-receivers. The circuits of the tele;

phone're'ceivers andtransmitters include induction-coils 25, as is ordinarily the case.

The circuits shown in Fig. 3 are similar to those of Fig. 2, except that each central-station switch" employed has two contact-arms,

of the system is connected, each such switch- Wire is connected through.a non-inductive resistance 16 to theswitch-arm 26 of its own switch and to one of the second row of contact-pieces of 'each of the other switches. The result of'this arrangement is that both sides of the telephone-circuits pass through the central-station switches, and the talkingcircuit established between any two stations isentirely distinct from that of any other stations, except for the battery connections.

The operation of the circuits and instruments shown in Fig. 3 is the same as that shown in Fig. 2, and hence requires no special description.

The arrangement of circuits and instruments shown in Fig. 4 is similar to that shown in Fig. 2, except that the retardationcoils are not interposed directly between battery bus-bar 19 and their several telephonewires, but are each in a local circuit 27, connecting the battery bus-bar 19 with the normal contact-point of the central-station switch to which each particular retardationcoilbelongs. When two stationsas,for example, station D and station F-are in communication, therefore, the telephonic circuit is from the receiver-hook switch of station D through telephone-wire 8 of that station and.

through central-station switch D to the telephone-wire 8 of station F, thence through receiver-hook switch of station F (said hook being up) and the telephone receiver and transmitter of that station and switch-Wire 10 of station F to bus-bar 15, and thence through switch-wire 10 of station D and the telephone transmitter and receiver of that station back to the receiver-hook switch. Battery 12 is bfidged across this circuit by wires (continuations of the switch-wires 10) leading from the positive pole of battery 12 to the point of connection of such wires with thebranches thereof connected to bus-bar 15 anii by a wire 27 leading from the negative po e 13 to switch F, and thence to telephonewire 8 of station F, which wire, asalready stated, forms a part of the telephonic circuit. It will be seen that with this arrangement only one retardation-coil is used.

It is obvious that one or more of the lines connecting each subscribers station with the central station may include ground. In particular the common return line may be formed by grounded connections.

Referring to Fig. 1, it will be noted that if the magnets of the automatic central-station switches are not of high-inductive resistance they themselves afiord a path for the tele-v phonic fluctuations which is the equivalent of the path formed by non-inductive resistances 16 and-17 and bus-bar 15. In practice if. the resistance of the switch-magnets is more than-ten ohms I prefer to use the shunt of battery 12 through a retardation-coil connection containing the non-inductive resistances and busbar, as shown in Fig. 1.

The. switch-magnets may themselves be caused to constitute the inductive resistances necessary in the bridge-circuit for the opera tion of the system, no other inductive resistance being required. This is illustrated in Fig. 5, which is a figure similar to, Fig. 1,

showing two subscribers stations H and I and a central station K. The receiver-hook switches, telephone-receivers, and callingtransmitters are designated by the same reference-numerals as in Fig. 1, as are the switch-magnets and the switch-contacts and the central-station@ battery. Return-lines (here numbered 30 and 31) extend from the upper contact-points of their respective receiver-hook switches to the bus-bar of the central-station battery, and the service-conductors (here numbered 32 and 33) extend from the receiver-hooks to their respective switch-magnets 4-and 5, respectively, from which a bridge connection 34 leads to the opposite pole of the battery. Between each switch-magnet and the'movable contact-arm of the switch a non-inductive resistance 35 is interposed. Conductors 36 connect the contact-arm of each switch with a contact-point of the other switch, with which the contactarm thereof is adapted to make contact. The calling-transmitters 3 are connected to their respective telephone and switch wires.

insure'that the raising of a receiver-hook switch and the consequent completion of a battery-circuit through its transmitter and receiver shall not operate the corresponding central-station switch. These resistances likewise serve to reduce the battery-currentto the strength best adapted for the telephone instruments. Supposing that the calling-transmitter at station Hbe operated, a telephonic circuit is thereby completed from station H through conductor 32 to the central station, thence through non-inductive resistance 35 of the corresponding central-station switch,' and through the switch connectionG and conductor 36 to the non-inductive resistance of the switch corresponding to stationd, and thence through conductor 33, the receiver-hook switch at station I,

switch at station II back to the startingfor the operation of the central-station point. As in the preceding figures, it will be seen that the battery is bridged across the telephonic circuit, the self-induction of the coils of magnets 4 and 5 causing the telephonic fluctuations to pass from one station.

to another in preference to passing through the bridge-circuit. ,,It is obvious that in this.

arrangement if a number of subscribers stastation a single return-wire common to all of thesestations may lead to battery or that a ground connection may be employed. The call-bells and magneto-gencrators therefor rg may'be located in shunt-circuits 37, connecting the two sides of each subscribers' circuit, condenser-s or. other suitable means be ng employed to prevent wasteful fiow of-battery-currentthroughthese shunt connections. in :Fig. 6 I show thesame arrangement of circuits and apparatus applied to'a'system comprising three central-station switches,

) the return connections being through ground, however... The three subscribers stations tors, receivers; receiver-hoe "switches, and calling-transmitters and the switch magnets contact-arms are numbered as in the go e'ced111g..'figures, as"1s the central-station ubscigibers stations were centralgstatiQn are ,'tlir6ugli non-inductive resistance .35 to the ,g'gi; cbamcaa mtf its'switch,and thence to a contact point of each ofjthe other switches. It is also}connected by a bridge-conductor 34 to its switch-magnet, andthence to one pole nected on one side to the upper contact of the receiver-hook switch (there being no lower ,contact) and on the other side are connected to ground. Theb'ells 38 and generators 39 are in shunt-circuits leading from conductors 32 to ground, whichcircuits include condensers 40. it will be seenthat thisarrangemc'ntof circuits and instruments provides for communication between any .ofthe sta tions of the system, and for the operation of the central-station switches as well, all from y the central-station battery, and that nevertheless only one independent wire is required from each subscribers station to the central station, the return being either through ground or through acommon return conductor, as preferred. The simplicity of this system will be appreciated.

Figs. .1; and 6, in which a single circuit lor' each subscriber serves both' for talking and tions are located on one sideof the central- ,aretettered L, M, and N, and the central staij n iinberd 32.. Eachsueh wire" is connected;

In another application for Letters Patent conductor 18 and that a ringing-switch of a simple form, consisting, essentially, of a contact-arm 42, adapted to make contact-successively with a series of connected contactstuds 43, is shown interposed at each subscribers station between the switchingavire 11 and the telephone-wire 8 or 9. The D S employed may be vibrating bells or may be biased, being arrangedto move clappers in one direction when the battery-current is completed through them and to move them back as soon as the batterycurrent is discontinued. The operation of this arrangement is as follows: Supposing that the subscriber at station B has called the subscriber at station A, and so has completed communication between service-lines 8 and 9 through contact 7 of one of the central-station switches. When the subscriber at station E removes his receiver from its hook a circuit is complete from battery 12 through conductor 11 and the receiver-hook switch at station B and throu h conductors 9 and 8, the magnet of the ca l-bell at station A, (the receiver-hook at that station-being still down, of course,) and through the 'common return "conductor back to battery. The bells being biased, as above stated, at the completion of this circuit the bell at station A will give a short ring. The subscriber at station B may ring the bell at station A repeatedly by raising and lowering his receiver-hook switch or by operating his ringing-switch, the contactarm 42 of which completes the same ringingcircuit as the receiver-hook switch. As soon as the subscriber at station A responds and lifts his receiver from its hook or operates his ringing-switch, the conditions are reversed,

and if B has replaced his receiver on its hook, his bell is rung, thus notifying B that the call has been answered. v For the bells other signaling devices may be substituted." 6 p it is obvious that my invention is suscep [ib'le to many variations and modifications in location and arrangement of the C11- cuits and instruments, and I do not confine myself to the particular constructions herein shown and described.

Instead of employing a single centralstation battery for supplying current. both for talking and for operating the centralstation switches separatebatteries may be employed. This is illustrated in Fig. 8, which shows three subscribers stations I Q, R, a central station S, central-station switches P Q it and two central-staid on bata talking-circuit thcrefor, and the switching we of each station and the return connec-.

teries 44 and 45., Service-wires 46 connect each subscribersstation with the central station, where they divide, as in Fig. 6, one branch passing through the corresponding central-station switch-magnet and thence to battery 44, the other branch passing through non-1nductive resistance to the contact-arm t its central-station switch. Other servicewires 47 connecteach subscribers telephone instruments with the bus-bar ofthe centralstation battery 45. The opposite pole of battery 45-.i s connectedto the several'wires 46 common-return conductor in connection, as shown in the drawings, the

throu h inductive resistances 48. One side of'eae callin -transmitt er3 is connected to the correspon 'ng service-wire 46, the opposite side to a return-conductor 49, which may be a common-return conductor. For the round connections may of course be su stitutedQ The talking-circuit established by this system is as follows: Supposing stations P an R to be circuit is from the'receiver-hook of station P. through conductor .46 of that station, centralstation switch P, and. the central-station con? nections: to the wire 46' of station R, thence through the telephone instruments of that station, (the receiver-hook being up) and through the wire 47' of station R to the busbar ofb'attery 45, and thence through wire 47 of station P and the telephone instruments of that station 'back to the starting-point.

The battery is brid ed across this circuit through the wires inc uding the inductive resistances 48, and because of the fact that all the wires47 are connected toone-pole of the. battery. This s stem, involving the-use of the two batteries, orms the subj ect-matter' of a divisional application for letters Patent,

tiled January'21, 1-904, Serial No. 189,976.

Having now fully described my invention,

what Iclaim is 1.. In an automatic tele hone system, the l co'mbination with a centre station, a plurality. of subscribers stations, a service and a swit chingwire connecting each subscriber's station with-the central station, the'iatter conductor having return connections independent of the ser 'ice-wire, the service and switching wires of each station constituting tions therefor constituting a switching-circu1t,- and means at the central station for operatively connectin matic switches each having elec rically-operated contact mechanism including an operatin gmagnet-,, permanently included in the corresponding switching-circuit, of means at the central station for supplying electric current, connected to the several talking- -c1rcu1ts in common and to t] x;e several switching-circuitsin common, and telephone instruments and means for operating-said centralservice an the talking-circuits .of the different subscri ers, (iQjllniSlng auto 2. In an automatid tele hone system, the combination with a centre station, a plurality of subscribers stations, a service and a stationswitches, atv the several subscribers" stations.

conductor havingreturn connections inde-" pendent of the service-wire, the service and switching wires of each station'constituting a talking-(siicuit'therefor, and the switchin wire of each station and the return connections :therefor constituting a switching-circuit, and -means at the central station for o erativel connect the talking-circuits o the d' ferent su scribers, com rising automatic switches each having e ectrically-operated contact mechanism including an o erating-' magnet permanently included in t e corre' sponding switching-circuit, "of means at the central station for supplying electric current for talking and switching, comprising a source of electrical energy bridged across ltalki -circuits which are'connected by said centra -station; switches, and telephone instrumentsand means for operatin said.

scribers stations. 4 I

3. In anautomatic telephone system,

.the .combination'with a central station, a

central-station switches, -at.theeevfera subv plurality. of'subscribers"'stations, a service and a'switchingwire connecting each subscribers station-with the central station, the latter' conductor having return connections inde endent of the service-wire, the

i 8 switching wires of each station constitut' a tal -circuit "therefor, and the switchlng wire 0 each station and the rcturn connections therefor constituting a switching-circuit, and meansat the central 'station for operatively connecting the talk-- lug-circuits -of the different subscribers, comprismg automatic switches each having electrically-operated contact mechanism in-' eluding -an operating-ma net permanently included in the correspo ilding switchingcircuit; of a common source of} electrical energy for talklng and switching,,,included in both the talking and switching circuits of "each subscriber,.. and telephone instruments and means for operating. said central-station swatches, at the several subscribers stations.

4. In an automatic telephone system, the

combination with a central station'ya: plural- 7. switching wire connecting each subscribers 4 a station with the central station, the latter sponding bridge circuit, and. returnconnec-- tions for the switching-wires, forming therewith switching-circuits in which thecommon source of electrical energy and the corresponding switch-magnets are included, .of telephone instruments and means for operating said central-station switches, at the several subscribers stations.

5. In an automatic telephone system, the combination with a central station, a plurality of subscribers stations, subscribers circuits connecting said subscribers stations and the central station, and means at the central station for connecting subscribers circuits comprising automatic switches each having electrically-operated contact mechanism including an operating-magnet permanently bridged across a corresponding subscribers circuit, of a common source of electrical energy included in common in the bridge connections of said magnets, resistance interposed between the switch-magnet of each subscriber and the switch-magnets of the other subscribers, and telephone instruments and means for operating said central-station switches, at the several subscribers stations.

6. In an automatic telephone system, the

combination with a central station, a plurality of subscribers stations, service, switching and return wires connecting each subscriber s station with the central station, and means at the central station for connecting operatively the subscribers talking-circuits, comprising automatic switches each having electrically-operated contact mechanism including an operating-magnet included in a switching-circuit comprisingthe corresponding subscribers switching-wire and the return-wire, of central-energy means for supplying current to said .circuits for switching and for conversation, comprising a-battery bridged across the service and. switching wires of the several subscribers, telephone instruments at the subscribers stations in talking-circuits comprising the said service and switching wires, and means at the subscribers stations, for operating the centralstation switches, included in the said switching-circuits.

7. In an automatic telephone system, the

combination. with a central station, a plurality of subscribers stations, service, switching and return wires connecting each subscribers station with the central station, and means at the central station for connecting operatively the subscribers talking-circuits, comprising automatic switches each having electrically-operated contact mechanism including an operating-magnet included in a corresponding switching-circuit comprising the corres onding subscribers switchingwire and tile return-wire, of. central-energy means for supplying current to said circuits for switching and for conversation, comprising a battery bridged across the service and switching wires of the several subscribers, telephone intruments at the subscribers stations, signaling means at the subscribers stations, switches arranged to form talking-cir euits through said telephone instruments and the talking and switching wires, or signalingcircuits through the switching and return wires, and means at the subscribers stations for operating the central-station switches.

8. In an automatic telephone system, the

- combination with a central station, aplurality of subscribers stations, a service and a switching wire connecting'each subscribers station with the central station, the latter conductor having return connections independent of the service-wire, the service and switching wires of each station constituting a talking-circuit therefor, and means at thepcentral station for connecting the talking circuits of thedilferent subscribers,.comprising automatic switches eachhaving contact mechanism comprising contacts for connecting the several service-wires and other contacts for connecting the several switching-wires and an operating-magnetincluded in the switching-circuit comprising the corresponding subscribers switchingwire and, the return connections thereof, of means at the central station for supplying electric current, connected to the several talking-circuits in common and to the several switching-circuits in common, and means for operating said central switches, at the several subscribers stations.

9. In an automatic telephone system, combination with the central station, a plurality of subscribers stations, subscribers circuits connecting said subscribers stations and the central-station, for conversation and for operating central-station switches, and means at the central station for connecting subscribers talking-circuits comprising automatic switches each having electrically-operated contact mechanism comprising contacts for both sides of said talking-circuits and an opcrating-magnet permanently bridged across a corresponding subscrib ers .circuit, of central-energy means for supplying electric current for talking and switching comprisin a common source of electrical energy included in common in the bridge connections of said magnets, and telephone instruments and ANTHONY VAN WAGENEN. Witnesses CAL BRADSTREET, EDWIN J. S'rAsoN. 

